Designation:F2358–04StandardGuideforMeasuringCharacteristicsofSapphireSubstrates1ThisstandardisissuedunderthefixeddesignationF2358;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidecoversanondestructiveproceduretodeter-minetheformofclean,drysapphiresubstrates.1.2Thisguideisapplicabletosubstrates25mmorlargerindiameter,withaminimumthicknessof100µm.Thisguideisindependentofsurfacefinish.1.3Themeasurementsdescribedinthisguidemaybeappliedtotheentireglobalsurfaceofthesubstrate,ortosmallerlocalizedareas.1.4Thevalueofthemeasurementsdescribedinthisguidewillbeaffectedbytheamountofedgeexclusion(thatis,theareaaroundtheperimeterofthepartwhichisignored).Theamountexcludedshouldbeagreeduponbytheproducerandconsumerusingthisstandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatoryrequirementspriortouse.2.ReferencedDocuments2.1SEMIStandard:2M3SpecificationsforPolishedMonocrystallineSapphireSubstrates3.Terminology3.1GeneralDefinitions:3.1.1backsurface—thesurfaceoppositethefrontsurface.Ifthereisnodifferencebetweenthefrontandbacksurfaces,thenthesurfacesmaybedeterminedarbitrarily,andarethereforeinterchangeable.3.1.2best-fitplane—thetheoreticalplaneestablishedbyusingtheleastsquaresfitmethod,basedondataobtainedfromthequalityareaonly.3.1.3best-fitsphere—thetheoreticalsphereestablishedbyusingtheleastsquaresfitmethod,basedondataobtainedfromthequalityareaonly.3.1.4frontsurface—thepreferredsurface,asdefinedbytheuser.3.1.5qualityarea—thecentralareaofawafersurface,definedbyanominaledgeexclusion,overwhichthespecifiedvaluesofaparameterapply.Ifthequalityareaisnotcircular,the“circledefiningthequalityar...
